package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock{

    private String name;

    private StringRedisTemplate stringRedisTemplate;

    private static final String KEY_PREFIX = "lock:";

    private static final String ID_PREFIX = UUID.randomUUID().toString(true);

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        String key = KEY_PREFIX + name;
        long threadId = Thread.currentThread().getId();
        String value = ID_PREFIX + threadId;

        Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(
                key,
                value,
                timeoutSec,
                TimeUnit.SECONDS);

        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unlock() {
        //获取线程标识（防止误删别人的锁
//        long threadId = Thread.currentThread().getId();
//        String value = ID_PREFIX + threadId;
//
//        String key = KEY_PREFIX + name;
//        String id = stringRedisTemplate.opsForValue().get(key);
//
//        if (value.equals(id)){
//            stringRedisTemplate.delete(key);
//        }

        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId()
        );
    }
}
